This longitudinal investigation is concerned with antisocial and violent behavior in childhood and its mental health consequences in later development. The research will provide outcome measures in adolescence and early adulthood for males and females who have been individually assessed on an annual basis since childhood. The core longitudinal sample includes 695 subjects who have been tracked annually for six to nine years, with subgroups of high aggressive subjects and individually- matched controls embedded in each of two cohorts. In 1988, 100% of the original living subjects were located and over 98% were individually assessed. In this terminal phase of the research, subject will be seen in the year after they complete high school (in the case of school dropouts, in the year they should have completed high school). They will be at a critical transition stage in the life cycle -- 18-20 years of age -- when they are expected to be vulnerable to a range of mental health consequences. The research measures are multi-level and transgenerational. The aim is to determine the sequelae of conduct problems observed in childhood and adolescence. Special attention will be given to the occurrence of subsequent patterns of abuse, both within and outside the family. Persons in the effective familial system (parents, grandparents, spouse, and children) will be individually assessed, and analyses will be made of public records. This outcome information will be integrated with the prospective longitudinal data on aggressive and violent behavior obtained in childhood and adolescence. Both person- oriented and variable-oriented parametric analyses will be employed. The research team is an interdisciplinary one which involves collaborating investigators whose scientific training has been in psychology, psychiatry, internal medicine, education, and ethology. It is anticipated that the findings will have useful implications for understanding the etiology, course, and cross-generational transmission of physically assaultive behaviors.